The invention relates to the esterification of furfuryl alcohol and its derivates by means of aliphatic acid anhydrides, with aliphatic tertiary amines as catalysts. According to the invention the compounds obtained by the method can as such be used as biologically active substances against, for example, molds, fungi or bacteria or as intermediates in the production of such slimecides. These compounds can also be used as fragrancies.
It is generally known that ordinary alcohols can be normally esterified with acid anhydrides, using acids or bases as catalysts. It is also known that furfuryl alcohol and several substituted furfuryl alcohols decompose and polymerize under acid conditions. For this reason the esterification of such substances cannot be normally performed by acid catalysis, using mineral acids, e.g., sulfuric acid, as a catalyst and the organic acid in question for the esterification. It is known, for example, that furfuryl alcohol can be esterified with acetic anhydride. [J. E. Zanetti, J. Amer. Chem. Soc. 47 (19250 pp. 535-536]. The synthesis is performed by heating furfuryl alcohol and various acid anhydrides at 130.degree.-150.degree. C for 2 hours. Yields are not mentioned. The normal method for preparing furfuryl alcohol ester of acetic acid is, however, to use acetic anhydride as the condensing agent and water-free (smelted) sodium acetate as an auxiliary condensing agent (Org. Synth. Coll. Vol. 2nd ed., John Wiley & Son, Inc., New York 1967, pp. 285-286). The synthesis is performed by using benzene as the medium and the reflux temperature of benzene as the reaction temperature. After the reaction the mixture is poured into water, it is neutralized with sodium bicarbonate solution, the benzene solution is washed with water, and the benzene is distilled off. Thereafter the product is distilled. The drawbacks of the method are the great need for water-free sodium acetate, the neutralization of the mixture after the reaction, the distillation off of the auxiliary agent benzene and in addition, a yield of only 87-93%, consisting of a product with a concentration of 93-94%.
Poorly water soluble derivates of furfuryl alcohol, such as 5-nitro-2-furfuryl alcohol, can also be esterified by acid catalysis by means of, for example, sulfuric acid (M. Ja. Buklava et al., Latvijas PSR Zinatnu Akad. Vestis, Kim. ser. (1963):3, pp. 349-355). The drawback of this method is that, for example, isopropanol must be used as the medium and the yields are usually approx. 80%. The method is not applicable to, for example, furfuryl alcohol.